Fix: doc preview src of local storage policy starts with ":/" (#1842) (#1844)

* Fix: doc preview src of local storage policy starts with ":/"

* Fix: doc preview src of local storage policy starts with ":/"

service/explorer/file.go

@@ -227,8 +227,14 @@ func (service *FileIDService) CreateDocPreviewSession(ctx context.Context, c *gi
 		return serializer.Err(serializer.CodeNotSet, err.Error(), err)
 	}
 
+	// For newer version of Cloudreve - Local Policy
+	// When do not use a cdn, the downloadURL withouts hosts, like "/api/v3/file/download/xxx"
 	if strings.HasPrefix(downloadURL, "/") {
-		downloadURL = path.Join(model.GetSiteURL().String(), downloadURL)
+		downloadURI, err := url.Parse(downloadURL)
+		if err != nil {
+			return serializer.Err(serializer.CodeNotSet, err.Error(), err)
+		}
+		downloadURL = model.GetSiteURL().ResolveReference(downloadURI).String()
 	}
 
 	var resp serializer.DocPreviewSession